Description: The Biostatistics and Data Management Core for this Program Project will provide both biostatistical and data management expertise in support of all projects as well as of Cores C, D, and E. The Core leader is Dr. Donna Speigelman, Associate Professor of Epidemiology and Biostatistics at Harvard School of Public Health. She, together with Dr. Janet Forrester, will co-direct this Core. Drs. Speigelman and Forrester will meet weekly with staff of Core B to discuss and to coordinate the Core?s activities and will attend individual Program Project meetings as necessary in order to satisfy the statistical demands of this Program Project. Communication will largely be facilitated by meetings and on-site visits by the leaders of the Biostatistics Core in order to achieve the goals of this Program Project.